Current-regulating arrangement for rectifiers



Jan. 3, 1928.

P. M. G. TQuLoN CURRENT REGULATING ARRANGEMENT FOR RBCTIFIERS FlecLDec.21. 1923 5 Sheets-Sheet l Jan. 3, 1928. f

P. M. G. TOULQN CURRENT REGULATING ARRANGEHENT Fon REcTIFIERs Filed Deo.21./1923 i Sheets-Sheet 2 Jan. 3, 192s. 1,654,949

P. M. G. TOULON 1 CURRENTREGULATING ARRANGEMENT FOR RECTIFIERS PatentedJan. 3, 1928. y

UNITED STATES l 1,654,949 PATENT oFFIcE.

PIERRE MARIE GABRIEL TOULON, OF PARIS, FRANCE, ASSIGNOR, BY IIESNEASSIGN- MENTS, TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

CURRENT-REGULATING ARRANGEMENT FOR RECTII'ZIERS.

Application led December 2 1, 1923, Serial No. 682,093, and in GermanyJanuary 4, 1923.'

My invention relates to current rectifiers wherein the current passingthrough the same will produce an aro between an incandescent cathode(iilament placed in a raren fied gas such as neon or argon) and raisedto incandescent by the passave of a current, or a bath of liquid metalI(for example a bath of mercury with cathodic spot maintained by a smallauxiliary arc), and one or In more anodes. It has for its object topermit of regulating and continuously varying the rectified current.

In three-electrode vacuum tubes one may pass between the filament andthe plate a l5 current whose value is regulated by varying the potentialof the grid. By analogy, it has been proposed for arc apparatus of theabove-mentioned type, to place in thepath of the arc a cooled grid whosepotential can 2U be varied in order to influence the current passingthrough the rectifier; it has been further proposed to place around theapparatus the conducting body whose potential is varied in order to actupon the current in an electrostatic manner and to regulate its value.The apparatus which can be thus devised may be employed for example asconverting apparatus, amplifiers, or genera-- tors of current of high orlow frequency, according to the knowny dispositions. In these vaporelectric apparatus, the electrostatic action can advance or retard theformation of the arc. But when the arc is once formed between thecathode and an anode, it is impossible to extinguish it by means of saidelectro-static action. It is a sort of mishit regulation. It will followthat with the devices hitherto in use, one cannot completely varyat willin a progressive manner the value of the current supplied by an anode.In particular, when the apparatus is supplied from a source ofalternating current and operates as in a rectifier or an amplify-.1'-

ing device, it becomes impossible to obtain the desired voltage andcurrent in the work circuit.

This drawback does not occur with the three-electrode tubes and it is infact recognized that by varying the potential of the grid one can modifyin a continuous manner the value of the current between the filament tothe plate. But on the other -hand the three-electrode .tubes will notrender the same services as the vapor electric or are 5 apparatus, forthey can only supply a relatively small current, even for large-Sizedbulbs, wlule the fall of tension in the em ty space between filament andplate is consi l erable, andthe efficiency is low.

My said invention has for its object, by obviatmg the above-mentioneddrawback, to render feasible for the arc apparatus fed by alternatingcurrent nearly all the arrangements .and most of 'the applications whichwere hltherto restricted to the three-electrode tubes.

u The invention consists in providing an lnner or outer conducting bodyacting electrostatically upon the electric charges adjacent one ofelectrodes of apparatus not with ,a potential, as heretofore, eitherconstant or else, if alternating, in phase with potential ofcorrespondlng electrode or showing with same a constant phasedifference, but on the y contrary with an alternating potential showingwith potential of corresponding electrode a phase difference which canbe varied at will, so that the arc cannot be formed during a determinedfraction of the half period in which the corresponding anode ispositive. The invention is obviously applicable to a plurality ofelectrodes at the same time. The phase difference may be regulated sothat the arc of any given anode shall only remain active, in eachperiod, between two instants which can be determined at will, and itthus becomes feasible to var in a progressive manner the current suppied by the anode, as well as the potential difference of the rectifiedcurrent. The said device offers the means for obtaining not only anamplifier whose characteristic curve does not possess the abrupt bendwhich results from vthe known arrangements, but further, by a suitabledisposition, a voltage regulator or transformer, a starting rheostat, afrequencyreducing transformer and a phase compensator, as will be madeevident in the several applications of the saine which vare disclosedhereunder by way of example.

The variable phase-difference between the potential of an anode and thatof the inner or outer body which acts electrostatically thereon isobtained by any suitable means, and chiefly by the use of windingsproperly disposed in a polyphase revolving eld analogous to whatprevails for synchronous or non-synchronous motors or by means ofresistances, self-induction or capacities, according to known devices.

By way of example I have described hereunder and illustrated in theappended drawing various applications of the invention.

Fig. 1 relates to an apparatus having a single anode. The arrangementindicated may be used to advantage as an amplifier or a voltageregulator. The phase displacement of this tension is effected by meansof a variable self-induction. 0

Fig. 2 is a diagram showing the variations of potential and current inrelation to the time, in the anode-of the above-mentioned apparatus, andthe phenomena can be thus explained.

Fig. 3 relates to the use of a two-anode bulb. y

Fig. 4 relates to the case of an apparatus having a great number ofanodes supplied from a polyphase source; this device is chieflyadvantageous in providing a frequency changing apparatus or a phasecompensator.

Fig. 5 is a diagram relating to Fig. 4, showing the tension and currentin each anode, whereby the phenomena can be explained.

Fig. 6 relates to the case in which various cathodes are mounted in t-hebulb, whereby the directionof the current can be reversed at will.

Among the arrangements which the invention affords, the dispositionswhich are set forth hereunder are only intended to represent a few ofthe most interesting devices, and obviously I may provide many otherswhich are of a different nature while at the same time conforming to thespirit of the invention. Y

As shown in Fig. 1, the bulb l1 contains a mercury cathode 2 upon whicha cathodic spot is maintained by means of an auxiliary electrode 3supplied from a continuous current source 4, 4 through an adjustableresistence 5. The mercury anode 6 is connected to an alternating currentline 8, 8 (whose source 8 is between 8 and 8) through the work circuit 7comprising the apparatus A. A coating 9 which surrounds the anode 6 andexercises an electrostatic action upon the elect-ric charges isconnected to the cathode through the resistance 10, and to the otherterminal of the alternating current line 8 through the primary of asmall transformer 11 whose self-induction may be varied by progressivelyshort-circuiting the secondary upon a small variable resistance 12. Thetransformer 11 ina be replaced by a variable self-induction coil. Thebulb is preferably cooled by immersing it in an insulating liquid13 suchas oil. An analogous arrangement can be used with an arcappa` ratuscomprising a cooled grid placed in the path of the are.

s The current necessary to vary the potential of the coating 9 isextremely small with reference to the current in the external circuit 7,so that the resistance 10 and the selfinduct-ion l1 can be made veryhigh without inconvenience. Since the current therein has very smallvalue, they may have a greatly reduced size. Further, the tension of thesecondary circuit of the transformer 11 can be suitably chosen to enablean economical construction of the rheostat 12 which has on the otherhand the advantage of being electrically insulated from t e rest of thedevice.

The operation is as follows. The cathode is made active and ismaintained in operation by the electrode 3. The curve 14, Fig. 2, showsthe potential difference between the cathode 2 and the anode 6 inrelation to the time. The lower curve 20 shows the value which thealternating current would attain if it' could pass without interruptionthrough the appaiataus whose resistance is constant. Curve 15 representsthe potential difference between the cathode 2 and the coating 9. Thephase diierence between the two sinusoids 14 and 15, i. e. the distance16-17, can be continuously modified by acting upon the rheostat 12. Aslong as the potential lof the coating 9 with reference to the cathode 2is below a certain value reprel sented b the horizontal line 18, the arccan` not be formed between the anode and the cathode. When thispotential 18 is attained at 18', the are will be formed, and thepotential diiference between anode and cathode (curve 14) has a value 19which is low and is substantially constant (about 11 volts for a mercuryare); this potential difference is represented by the horizontal line19. At the same time the value 2O of the current in the anode (lowercurve)y which was practically nil at 20 will rise abruptly to a ratherhigh value 20 depending -upon the phase difference and theself-induction of the circuit. In Fig. 2 it is supposed that the workcircuit has no self-induction, so that after the lighting of the the arctakes place, the current will vary according to a sinusoid 20, 20 untilthe supply tension (curve 14) at the point 19 becomes less than thetension 19 which must prevail between the electrodes for the maintenaceof the arc, and hence they arc will be extinguished. 'Ihe same effectswill occur at eachI alteration.

Fig. 3 shows an arrangement with tivo anodes. The supply transformer 21having a middle neutral point supplies the external work circuit 22.This circuit is connected to the cathode 23 whose cathodic spot ismaintained by the auxiliary anode 24. The anodes 25, 26 are supplied bythe transformer andare connected to its two ends 21', 21". The coatings27, 28, connected at 21 to the neutral point of the transformer 21, willhave an electrostatic action upon the free electric charges and Willretardl the lighting. Their lou . that for certain tubes and with anexcessive pressure of the mercury vapor, it will be impossible toregulate the current supplied, and that the are will not becomeextinguished. This drawback can usually be obviated by mountingadditional coatings such as 33, 34 along the walls, and said coatingswill be connected to the neutral point at 2 1 (connection shown in fulllines) or to the cathode at 23 (connection in dotted lines) or further,the coating 33 can be raised to a potential having a negativephase-diiference with re-vv spect to the anode, for instance byconnecting it to 26, and a like effect `can be obtained for the coating34 by connecting it to 25. By properly choosing the phases of thepotentials and of the coatings, and also the shape of the tube, it willbe almost always feasible to find the critical region in which theunstable condition of the arc will allow the regulating of the currentproduced, in accordance with the invention.

Fig. 4 relates to the use of a polyphase converting device having sixanodes,. The secondary of the 6-phase transformer 35 supplies the sixanodes 36, 37, 38, 39, 40, 41 each of which is provided with a rcoatingsuch as 42 (the coating may be replaced by a grid) having anelectrostatic action upon the electric charges. The cathode 43, which ismaintained by means of the auxiliary electrode 44, is connected to theneutral point of the main line through the medium of the work circuit 45a-ccording to one of the known arrangements for mercury vapor convertingdevices. Further, by the use of various ends brought out, or additionalwindings on the polyphase transformer, one can produce in a n'iagneticcircuit ofv small size 46 a rotating ticld analogous to those producedin motors, for instance by the use of the coils 47, 48, 49. The phase ofthe tension of any one of the coatings surrounding the anodes, such as42, can be varied by changing the position of itssupply coil in relationtc the other stationary coils 47, 48, 49 producing the rotating field.The six coils Y (such as 50) which supply the six coatings 42 may bemounted with a single movable core so as to constitute windings whichare analogous to the armature sections of a I of the core.

dynamo.l One can thus produce gradual variations in the current byslightly rotating the movable core in the revolving field. By actuatingthe said core in a continuous manner at al given speed, a pulsatingcurrent of variable vfrequency will be produced in the work circuit.,thus forming a frequency changing device. The arrangement can becolnpleted by the use of various apparatus analogous to the one abovedescribed, whereby a polyphase system will be obtained; for instance bythe use of three apparata I may constitute a three-phase systemoperating at the new frequency. The said movable core which has thereonthe windings 30 and whose variations ot' position change the potentialof the coatings 42, may comprise all the windings at once by a suitabledisposition of the several coils, as may be readily conceived.

Further the said revolving field arrangement for the device controllingthe coatings employing the coils 47, 48, 49, may be provided with allthe improvements which are known in the case of multiple windings fordynamos or stators having a certain number of poles, and it is subjectto a considerable range of variations.

The problem of constituting, in accordance with the invention, a phasecompensator or various devices for increasing the power factor, .may besolved in a very simple manner by a suitable choice of the potentials ofthe coatings. It will suiiice to select this potential in such mannerthat the output of each anode shall be in advance upon the maximumtension of the supply transformer.

According to the invention, apparatus may be constructed for theautomatic comloo pensation of the drop in voltage on the lines y of amain supply circuit. As I have already shown, it is feasible to vary atwill and in a continuous manner the voltage or the current in thecircuit supplied by the said apparatus, by changing the value of aself-induction or of a resistance suitably connected to the coating (orgrid) or acting 'directly thereupon. Itis evident that this variationcan be controlled by the displacement of a movable coil of agalvanometer which serves as a voltmeter or an ameter. It is also knownthat the value of the self-induction of a coil with iron core will varywith the saturation This saturation varies with the magnetizingcurrentacting upon the core. It will. be an easy matter to obtain cause andel'ect relations between such phenomena by means of suitablearrangements of apparatus and circuits. For instance 'I mayautomatically increase the line voltage inv l relation to the output,andl obtain what is often designated as compounding, by ena-` ployingthe line current itselflto saturate the core of the self-inductionfcoilby the proper disposition of "windings thereon. This self-induction coilwill regulate the line voltage by acting upon the coatings (or grid) byan arrangement of circuits and devices as above indicated.

The operation of the converting apparatus indicated in Fig. 4 as avoltage regulator or starting rheostat is shown diagrammatically in Fig.5, which represents at the upper part the six sinusoids of the G-phasecircuit, these being displaced in phase. The lower sinusoid 5lrepresents the potential difference between the neutral point and one ofthe anodes. The toothed curve 52 (full lines) at the top, represent thevalue of the current produced. The curve with flat parts 53 (full lines)at the bottom, represents the potential difference between an anode andthe cathode. The curve 54.- represents the potential difference betweenthe cathode and the coatings.

The operation of the device will be readily understood with reference tothe explanations given for the apparatus Fig. 2.

As long as the potential of 54 (dil'eren'fe between the cathode andcoating) is below a certain critical value 54, the anode (such as 3l)cannot be lighted. But when the said value is attained, the anodebecomes lighted and it will remain lighted until the succeedingelectrode can be lighted in turn due to the value of the potential ofits coating. Fig. 6 shows a special arrangement applicable to the casein which the converting device comprises a plurality of cathodes, twofor instance, enabling the reversal of the current in the bulb at willat any given moment, and also the regulation of the value of thiscurrent. Eachoi the cathodes 55, 56 are maintained by two auxiliaryelectrodes 57, 58 supplied by small independent continuous currentsources. The coatings 59, 60 allow of preventing the formation ofthe-arc in one or the other direction. For this purpose the coating 59is connected to the cathode 56 through a winding 62 producing a. certainE. M. F. which is variable in current and in phase. In like manner, 6()is connected to 55 through a winding 61 which produces a certain E. M.F. variable in current and in phase. The coils 61 and 62 can be moved inthe revolving field 63. In these conditions, if the apparatus issupplied by a source of alternating current, I may vary at will thedirection and value of the current in the bulb, by a suitable choice ofthe value and phase of the tensions upon the coatings. For this reason,the latter disposition will be preferable to that of the convertingdevices in common use, from t-he fact that each electrode can beoperated as a cathode or an anode as desired, and this will enable theuse of a great variety of combinations of a valuable nature.

What I claim is:

l. The combination of an alternating current circuit, a load circuit, acontinuously excited vapor electric device provided with a cathode andanode connected between said circuits and with an electrode arranged tocontrol the current transmitted between said cathode and anode, andmeans arranged to vary t-he phase relation between the potentials ofsaid electrode and said alternating current circuit.

2. The combination of an alternating current circuit, a load circuit, acontinuously excited vapor electric device provided with a cathode andanode connected between said circuits and with an electrode arranged tocontrol the current transmitted between said cathode and anode, and aphase control device connected between said cathode and said electrode.

3. The combination of a current supply circuit, a load circuit, acontinuously excited vapor electric device provided with a cathode andan anode connected between said circuits and with an electrode arrangedto control the current transmitted between said cathode and anode, meansfor applying an alternating potential to said electrode, and meansinterconnected with said electrode for varying the phase of saidpotential.

4. The method of controlling the transmission of power between differentelectrical circuits through a continuously excited vapor electric deviceprovided with an electrode for controlling the transmission of currentbetween its cathode and anode, which comprises varying the phaserelation loe-y tween the potential of said electrode and the potentialof one of said circuits to vary the magnitude of said power.

5. The combination of a trical circuits, a continuously excited vaporelectric device connected between said cirs cuits, a control circuit forsaid device, and phase control meansconnected in said controlcircuit forvarying the magnitude of the power transmitted between said circuits.

6. The method of controlling the voltage of a direct current circuitsupplied with current through a vapor electric device provided with acathode and an anode and with an electrode arranged to control thecurrent transmitted between said cathode and anode, which comprisesapplying an alternating current potential to said control electrode, andvarying the phase of said potential.

7. The method of controlling the relation between the electricalconditions of direct and alternating current circuits interconnectedthrough a continuously excited vapor electric device provided with acathode and an anode connected between said circuits and with a controlelectrode, which comprises energizing said control electrode at the samefrequency as said alternating' current circuit, and varying the phaserelation between the potentials of said electrode and, said alternatingcurrent Circuit,

plurality of elec- 8. In a rectifier containing al1-atmosphere of a.voltage applied to said anode, and of rareed gas or vapor,thecombination means whereby said voltage is utilized to of an anode anda constantly energized cath-` control the phase of the voltage of saidcon- 10 ode arranged to produce an aro through said trol electrode.atmosphere, an outer control electrode ar- In Witness whereof I havehereunto set ranged to prevent ignition of said are during my hand.

a predetermined fraction of the half cycle TOULON, PIERRE MARIE GABRIEL.l

